PANNA: Alert: Tell EPA That Toxic Fumigants Must Go

The U.S. Environmental Protection Agency (EPA) is accepting public comments in their review of several soil fumigant pesticides that are especially problematic for workers and nearby communities. Soil fumigants are gaseous pesticides that are applied in large quantities before planting (50-400 pounds per acre) using outmoded technology developed in the 1920s that destroys all living organisms in the soil. More than 90% of these pesticides escape from the soil and drift off site, with high concentrations found in air more than a mile away from the application site in many cases. Among the most toxic chemicals used for pest control, fumigant use has resulted in many poisonings, and is linked to cancers, birth defects and sterility. This class of pesticides continues to be responsible for major acute poisoning incidents in communities in California's Central Valley, and is a significant contributor to the region's poor air quality, which is among the worst in the nation.

In July, U.S. EPA released the preliminary risk assessment documents for four fumigants-methyl bromide, metam sodium, dazomet, and 1,3-dichloropropene (Telone)-and will release an assessment for chloropicrin in mid-August. EPA has chosen to evaluate all of these pesticides as a group, in a Fumigant Cluster Assessment process, to "ensure that its assessment approaches are consistent, and its risk management decisions fully consider the risks and benefits of each chemical on an equal footing." The agency is also considering a new fumigant, methyl iodide, an extremely dangerous carcinogen, as a replacement for methyl bromide.

Fumigants are applied by injection into the soil, by sprinkler application or via drip tape. After application, fields may be covered with a plastic tarp or a layer of water to "water in" the fumigant and slow its release from the field. Neither of these measures effectively prevents fumigant drift, which is most likely to occur in the first three to four days after application, but remains a risk for several weeks.

Workers applying the chemicals are most vulnerable to exposure, but drift-prone soil fumigants also present special concerns for workers in adjacent fields and people who live, work and go to school near the application site. Just midway through the assessment process, EPA has already acknowledged that near-field concentrations of legally applied metam sodium, the pesticide responsible for multiple acute poisonings in California, are substantially higher than "acceptable" levels.

In 2002 PAN North America compared California Air Resources Board monitoring results for the fumigants methyl bromide, metam sodium and 1,3-dichloropropene with concentrations deemed "acceptable" by the California Department of Pesticide Regulation and found that even when correctly applied, fumigants typically drifted off site in concentrations substantially exceeding "acceptable" exposure levels for both short-term and seasonal exposures for many Central Valley residents.

To fully protect the health of workers and nearby communities, EPA needs to work with the U.S. Department of Agriculture to provide incentives for farmers to move away from this outdated technology and should put all of these chemicals on a phase-out schedule. Until then, substantial restrictions on their use, such as expanding protection zones around application sites, limiting the area treated during a specific time period, reducing application rates, modifying application techniques, and/or capping the total amounts used in a particular geographic area over a specific time period are important restrictions that should be implemented as soon as possible.

PANUPS is a weekly email news service providing resource guides and reporting on pesticide issues that don't always get coverage by the mainstream media. It's produced by Pesticide Action Network North America, a non-profit and non-governmental organization working to advance sustainable alternatives to pesticides worldwide.

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